The present invention relates to a method of loading a negative pressure type slider and further to a magnetic disk apparatus.
Generally, in magnetic disk apparatus there is a used a floating type slider having a magnetic head to perform the recording/reproduction of data. In order to position the magnetic head at a desirable track of a disk, a flexible member (which will be referred to as a flexer) is fixedly secured to an arm movable in directions traversing the tracks of the disk, and the floating type slider is attached to a tip portion of the flexer. Generally, a positive pressure type slider is used as the floating type slider. The operation of the slider thus arranged will be described hereinbelow.
At the time of the magnetic disk stopping, the slider is pressed by a constant load onto the magnetic disk surface and still comes into contact therewith for a while after the start of rotation of the magnetic disk. Thereafter, when the rotation speed of the magnetic disk exceeds a predetermined value, a positive pressure to be applied to the slider due to an air flow generated on the magnetic disk surface is balanced with the load acting upon the slider, and therefore the slider is floated and kept at the balancing position. Further, when the rotation speed of the magnetic disk decreases, the positive pressure decreases so that the slider again comes into contact with the magnetic disk surface and then stops. However, such an action causes the rubbing between the slider and the magnetic disk surface to generate the abrasion powder and damage them and further causes the adhesion between the slider and magnetic disk surface due to moisture on the magnetic disk surface. Thus, as a recent floating type slider, there has been proposed a negative pressure type slider which is arranged to be floated from the magnetic disk surface without contacting therewith. A magnetic disk apparatus using this negative pressure type slider will be described hereinbelow with reference to FIGS. 1 and 2A to 2C. In FIG. 1, illustrated at numeral 1 is a flexer which is constructed by leaf springs and illustrated at numeral 5 is an arm arranged to be movable in directions traversing data tracks recorded on a disk 6. The flexer 1 is bent at the vicinity of the arm 5 and fixedly secured to the arm 5 so as to generate a restoring force in a direction that the flexer 1 separates from the magnetic disk 6. Numeral 2 represents a gimbal constructed with a thin plate and fixedly secured to a top portion of the flexer 1. A slider 3 is attached to the gimbal 2. The gimbal 2 twists at the time of the rolling action and pitching action of the slider 3 and the slider 3 follows the magnetic disk 6 to float. FIG. 3 is an illustration for describing an arrangement of the slider 3. In FIG. 3, illustrated at 3a is a slider body constructed with a magnetic material such as a ferrite. In the slider body 3a there is provided a floatation rail 3b for generating a regulated pressure, and in the floatation rail 3b there is provided a step portion 3c. Further, illustrated at 3d is a concaved portion surrounded by the floatation rail 3b. In the concaved portion 3d there is generated a negative pressure. Still further, 3e and 3f are cores respectively coupled to the slider body 3a through non-magnetic materials 3g and 3h arranged to as act as magnetic gaps, and 3i designates lead wires wound around the core 3e. Here, the magnetic recording/reproduction is effected only by the core 3e. Air flows from an inflow side indicated by character A to an outflow side indicated by character B.
Referring back to FIG. 1, illustrated at numeral 4 is a flexer-pressing member which is constructed by bending a wire made of a shape-restorable alloy so as to have a V-shaped configuration, the flexer-pressing member 4 being fixedly secured to the arm 5. This flexer-pressing member 4 is arranged so as to store the shape to displace so that the flexer 1 becomes close to the magnetic disk 6 side when the shape restores. In response to being responsive to generation of heat due to flow of a current, the shape of the flexer-pressing member 4 is restored whereby the flexer 1 is displaced in the closing direction to the magnetic disk 6 so as to cause the slider 3 to float above the magnetic disk surface.
The operation of the magnetic disk apparatus thus arranged will be described hereinbelow with reference to FIGS. 2A to 2C. In FIG. 2A, the rotation of the magnetic disk 6 exceeds a predetermined speed and a current is then supplied to the flexer-pressing member 4, the shape of the flexer-pressing member 4 is restored so that the flexer 1 displaces to direct to the magnetic disk 6. In the state as illustrated in FIG. 2B, a positive pressure and negative pressure do not occur with respect to the slider 3 and the slider 3 is kept to be substantially parallel to the magnetic disk surface. In response to the displacement of the flexer 1, a positive pressure is generated with respect to the slider 3 so that the slider follows the magnetic disk 6 irrespective of occurrence of vibration of the magnetic disk 6 and vibration of the arm 5. Further, in response to the displacement of the flexer 1, the positive pressure gradually becomes greater and the slider 3 further becomes closer to the magnetic disk 6 with the state being kept as it is. When the flexer 1 takes the state as illustrated in FIG. 2C, i.e., when the flexer 1 approaches the magnetic disk 6 up to a predetermined distance, a negative pressure starts to gradually occur with respect to the slider 3 so that the slider 3 is drawn to the magnetic disk 6. Further, the slider 3 is floated so as to keep a constant distance with respect to the magnetic disk 6 with the positive and negative pressures generated with respect to the slider 3 and the restoring force of the flexer 1 being balanced with each other.
There is a problem with such a conventional arrangement, however, in that the magnetic disk apparatus have various relations in position between the flexer 1 and the arm 5 due to the errors on assembling the parts to vary the distance between the magnetic head and the magnetic disk 6. Accordingly, for instance, in the case that the distance between the magnetic head and the magnetic disk 6 is widened, difficulty can be encountered to cause the magnetic head to approach the magnetic disk 6 up to a desirable distance allowing sufficient generation of the negative pressure for the loading. On the other hand, in the case that the distance between the magnetic head and the magnetic disk 6 is narrowed, irrespective of the loading state being completed, the magnetic head can come into contact with the magnetic disk 6 to thereby cause crushing due to the excessive pressing force.